Straight-edge.



J. RIIKONEN.

STRAIGHT EDGE.

APPLICATION FILED MAY 20,1909.

Patented NOV. 7, 1911.

JOHN RIIKONEN, OF CHICAGO, ILLINOIS.

STRAIGHT-EDGE.

1,co7,so1.

Specification of Letters Patent.

Patented Nov. 7, 1911.

Application filed May 20, 1909. Serial No. 497,234..

To all whom it may concern:

Be it known that I, JOHN RIIKQNEN, a subject of the Czar of Russia,residing in the city of Chicago, county of Cook, and State of Illinois,have invented a new and useful Improvement in Straight-Edges, of whichthe following is a specification.

The object of my invention is to provide a straight edge of severalparts for the particular use of paper hangers the parts of which can beseparated and thereby easily transported by the user from place to placeon trolley cars and other conveyances for passengers.

The manner in which I accomplish my object is described in the followingspecifications and illustrated in the accompanying drawings in which:

Figure 1 is a top plan, the two main parts being locked together readyfor use. Fig. 2 is a top plan showing the male part of the lockingjoint. Fig. 3 is a top plan showing the female part of the lockingjoint. Fig. 4: is a cross section on the line 4-& Fig. 6. Fig. 5 is avertical elevation of a key required to lock the joint. Fig. 6 is anunderneath plan of the joint showing the locking cam.

In the drawings A and A are the two main parts of the straight edge madepreferably of wood, and of any desired length, thickness and width. Theunderside of these parts are recessed the full length, and in width therecesses are adapted to leave a narrow margin B along each edge. Thisform of the underside is adapted to reduce the contact of that side ofthe straight edge with the paper on which it is placed to the margins B,whereby the firmest pressure can be applied to the paper and contactwith paste and other matter on the paper be reduced to a minimum. In thetop side of the parts A and A is a channel C parallel with and close tothe outer edge D. This channel extends the full length of the main partsand is adapted to form a guide for a cutting knife used with thestraight edge for trimming the paper. The inside wall D of this channelis vertical. The outside wall D is beveled outwardly as shown in Fig. 4.Covering the edge D from end to end and secured thereto is a metal angleplate E. One edge of this plate extends over the beveled wall of thechannel C and forms a lip E shown in Fig. 4; under which a part of theknife used is engaged as it is moved along the channel, the knife bladebeing thereby held close to the face E of the plate E. In the top sideof the part A is a recess corresponding in depth with the channel G intowhich it extends. Secured in this recess is a metallic tongue F. Oneedge of which is in line with the vertical wall D of the channel C.Projecting from the underside of this tongue and near its outer end is afixed rectangular bolt G having a transverse notch G as indicated by thedotted lines in Figs. 2 and 6. Secured to the end of the part A andshaped to correspond with the tongue F and channel C is a metallic plateI-I. Extending longitudinally through this plate and into the part A aretwo threaded bores in which dowel pins H are secured. In the top side ofthe part A is a recess I. The base and vertical wall of which isreinforced with a metal plate I which in width and depth correspondswith the recess in which the tongue F is secured in the part A, and inlength it is adapted to receive the tongue F. Secured on the end of thepart A and formed to correspond with the recess I is a metallic plate J.Extending longitudinally through this plate and into the part A are twobores K adapted to receive the dowel pins H Extending through thecentral part of the plate I is a rectangular aperture L adapted for theinsertion therein of the bolt G. Pivotally supported on the underside ofthe plate I is a cam M having apertures M This cam is free to beoperated in an aperture N in the part A as shown in Figs. 4: and 6.

When the several parts are constructed as described and illustrated theyare connected and locked together as follows: The separate parts A and Aare held in the po sitions shown in Figs. 2 and 3 with the end of thebolt G on the face of the plate I. The dowel pins H are inserted in thebores K. The parts A and A are then brought into a straight line, theinserted dowel pins acting as pivots. The bolt G thereby enters theaperture L. When the parts are thus joined the teats on the key 0 areinserted in the holes M in the cam M and the cam thereby revolved intoengagement with the bolt G. In this locking movement the part 0 of thecam enters the notch G As the cam is turned its .periphery pressesagainst the base ofthe notch G and thereby forces the metallic ends Hand J together. The same movement of the cam presses the edge F of thetongue against the vertical edge I of the plate I, and the gradualincrease of thickness of the cam acting on the side of the notch G drawsbolt G and tongue F against the face of the plate I and locks the partsfirmly together. The pressure of the cam in the three specifieddirections brings every connecting part solidly together, the two partsA and A being thereby brought into a straight line every time they areconnected and held there till released by the use of the key. It isobvious that both edges can be used either with angle plates orotherwise.

What Iclaim and desire to secure by Letters Patent is:

In a tool of the kind described, the combination of two main parts, atongue and socket adapted to form a fixed joint of said parts, with acam pivotally supported on said socket, said cam being adapted to beoperated with a key and to force said tongue and socket together inthree directions, longitudinally, transversely, and vertically,

thereby locking said joint and said parts as a complete and correctstraight edge as described.

- JOHN RIIKONEN. Witnesses:

THOMAS J. MORGAN, JOHN M. ERIKSEN.

Copies of this patent may be obtained for five cents each, by addressingthe "Commissioner of Patents.

Washington, D. C.

